Topic: Erosion & Mass Movement

Erosion moving sediments from one

location to another.

Gravity

FORCE behind all erosion.

Mrs. Burns in

between two fallen

rock boulders at

Niagara Glen

Burns 2007

Talus pile, Niagara Glen Burns 2007

Mount Rushmore

Frost Wedging and Talus Cones

Agents of Erosion (things that move

sediments)

Water

Wind

Ice (Glaciers)

Mass Movement

• Large section of land and/or snow moved by

gravity

Ex) landslide, soil creep, avalanches, mudslides

Landslide

Landslide in California

Major landslide hits homes in Southern California

A firefighter surveys damage caused by a mudslide that destroyed 15 homes in La Conchita, Calif.

http://www.youtube.com/watch?v=mknStAMi

a0Q

Creep

The top of the soil layer moves faster

than the soil beneath, causing the

young trees to bend down slope. As

the roots stabilize the soil, creep is

greatly diminished and the trees can

then grow straight.

The slow down slope movement of erosional debris has displaced

(arrow) a gas pipeline in northern British Columbia. Original position of

pipeline is indicated by white dashed line. The pipeline has been placed

on timbers to allow adjustment to continuing slope movement.

Photographer: L.D. Dyke, 2006

Avalanches

LOOSE SNOW

AVALANCHES

SLAB AVALANCHES

Involve motion of cohesive layer above a weak failure layer

Cohesive layer becomes an avalanche when cut around all its boundaries

by brittle fractures

Massive avalanche just

outside of Denver, CO, on

1/6/2007

200 ft wide & 15 feet deep

Mudflow

Mudflow-damaged house along the Toutle River, Washington. The height of the mudflow

is shown by the "bathtub-ring" mudlines seen on the tree trunks and the house itself

(Photograph by Dwight Crandell).

04:01 PM PST on Tuesday, December 18, 2007

Landslides on tracts clear cut by Oregon State University's College of Forestry

set into motion the flow of mud and debris that inundated homes and U.S. 30,

geologists and foresters say.

FQ:

What is the very slow movement of rock downhill called?